Boeing’s investigation focuses on the door panel, as carriers find loose parts

Air safety officials who last week examined the fuselage of a Boeing Co. 737 plane have turned their attention to four bolts they have been unable to locate and said they may expand their investigation beyond the Max 9 variant after several airlines found loose parts.

The bolts were intended to secure the door panel that suddenly broke loose on Jan. 5 when Alaska Airlines Flight 1282 climbed to cruising altitude with 171 passengers on board. When properly tightened, they prevent the panel from sliding up the twelve stopper tabs that secure it to the aircraft fuselage.

“We have not yet recovered the four bolts that are holding it back from vertical motion,” Clint Crookshanks, an NTSB engineer, said at a news conference Monday evening. “We have not yet determined whether they existed there. That will be determined when we bring the plug to our laboratory in Washington DC.”

Alaska Air Group Inc. and United Airlines Holdings Inc. have discovered loose bolts after the Federal Aviation Administration grounded the Max 9 and ordered airlines to inspect the planes. A missing washing machine was found on a plane in India, regulators there said Tuesday.

Investigators are trying to determine why a door plug on a Boeing 737 Max 9 blew off at 16,000 feet.

Jennifer Homendy, chair of the National Transportation Safety Board, said Monday that her agency would consider expanding the investigation to other 737 Max models. Such a move would bring a deeper investigation into Boeing and its manufacturing processes, adding to the setback as the US planemaker tries to return the plane to service and avoid a lengthy grounding.

“First and foremost, we have to find out what happened here on this plane,” Homendy said during the press conference. “If we have a larger system-wide or fleet problem, we will make an urgent safety recommendation to effect change.”

Shares of Boeing fell 2.3% at 9:45 a.m. in New York on Tuesday, extending their decline after falling 8% the day before. Supplier Spirit AeroSystems Holdings Inc., which makes the 737 Max fuselage, fell 3.3%.

Up and out

NTSB investigators said they determined that Flight 1282’s door panel moved upward before ejecting, causing a rapid decompression of the plane. Roller guide rails that normally allow the hinged panel, or plug, to swing out when the bolts are loosened, were broken.

The plugs cover an opening on the Max 9 that can be used for emergency doors. Some airlines, including United and Alaska, gloss them over because they aren’t necessary for their seat configurations.

United said Monday that there are signs of “installation problems” on some of its planes.

Airlines in India conducted a one-time inspection of all 40 Max jets for possible loose hardware. An airline found a missing nut and washer in the rudder area of ​​one plane, the Directorate General of Civil Aviation said on Tuesday. No Indian airline operates the Max 9 subtype.

Michael O’Leary, CEO of Ryanair Holdings Plc, one of Boeing’s biggest customers for the 737 Max, told the Financial Times in an interview that the planemaker “needs to improve quality control.” In December, Boeing asked operators of newer Max jets to inspect the rudder area for loose hardware after an international operator discovered a missing nut and the planemaker found a loose one on an undelivered plane.

Boeing CEO Dave Calhoun, who wants to increase production of the Max cash cow this year, canceled a meeting of executives this week and will instead hold a meeting on Tuesday focusing on safety.

Although the NTSB was able to explain in detail what parts came loose aboard Alaska Air Flight 1282, it has yet to be determined exactly why the accident occurred.

NTSB teams studying the plane, meanwhile, found “no discrepancies” between the door plug that blew Alaska Airlines Flight 1282 and the intact identical plug on the other side of the plane. The door panel has since been found on the ground, while other pieces of evidence, such as the cockpit voice recorder, turned out to be unusable.

As air safety investigators continue to gather evidence, Boeing took the first step toward returning its grounded 737 Max 9 planes to service, providing airlines with guidance on what inspections are needed to detect another midair fuselage blowout to prevent.

“As operators conduct required inspections, we remain in close contact with them and will assist in addressing any findings,” Boeing said in a statement. “We are committed to ensuring that every Boeing aircraft meets design specifications and the highest safety and quality standards.”

Before the Federal Aviation Administration allows the planes to return to the skies, airlines must complete “enhanced inspections, including both left and right cabin door exit plugs, door components and fasteners,” the FAA said in its statement. “Operators must also meet corrective action requirements based on inspection findings before returning an aircraft to service.”

Alaska Air Flight 1282 was carrying 177 passengers and crew when the panel cracked. The fact that there were no people in seats 26A and 26B and that there were no more serious consequences was purely coincidental, Homendy said.

First print: January 10, 2024 | 12:01 am IST